BEAM ON: Patrick O'Shaughnessy and Pat Glynn say this photo of Rock Center going up shows their dads at either end of the beam. Photo: J.C. Rice

The humiliating melt down of Rep. Anthony Weiner has reshuffled the 2013 mayoral race, with political insiders nominating City Council Speaker Christine Quinn and former Comptroller Bill Thompson as the new front-runners.

For all his fierce partisan attacks on Republicans in Washington, Weiner was viewed as the most moderate in the field of a half-dozen Democrats looking to succeed Mayor Bloomberg.

Quinn has the best chance of assuming that mantle.

“The establishment is starting to move toward Quinn,” said one veteran political consultant.

Thompson is the only black candidate in the race, and the only one to have previously run for City Hall.

If he pulls 75 to 80 percent of the black vote, as many assume he will, it’s difficult to see how Thompson doesn’t at least come in second — enough to get into a likely runoff in a multi-candidate race.

Thompson’s biggest problem at the moment is continued skepticism about his intentions.

“He told me he’s running,” said one business executive. “The question is, how is he raising the money?”

Thompson allies insist he’s in it to win it.

“Bill is out at a dozen events a week,” said one person in the Thompson camp. “He’s been quietly building a coalition.”

But when the next campaign financial filings are released July 15, there won’t be huge numbers next to Thompson’s name since he’s only been fund-raising for a few weeks.

Comptroller John Liu’s chances to move up are closely tied to what Thompson does.

“If Thompson is in the race, [Liu] can’t possibly be competitive,” said one source who knows both men. “Liu is very popular in black areas, but the black vote would all go to Thompson.”

Public Advocate Bill de Blasio’s hope of becoming mayor is closely tied to what Liu does.

Both appeal to the same progressive, union-affiliated constituency. Liu is also a powerhouse fund-raiser. If he enters the race, de Blasio’s chances would dim considerably.

Under the term-limits extension, Liu and de Blasio are allowed to serve two more terms in their current offices. Each would have to give up almost certain re-election all the way to 2021.

Manhattan Borough President Scott Stringer has a lot less to lose. He’s got only one term to go and, with Weiner gone, is the only Jewish mayoral candidate left.

With more than two years before the election, there’s still time for others candidates to jump in.

Police Commissioner Ray Kelly, for one.

“He’s at every event I go to,” said one staffer for an elected official.